Increase brightness in part of an image

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Hi, I was wondering if anyone would know if it is possible to do something like what I present in the following picture.
The image I'm interested in treating is one of 8000x8000 pixels size and in gray scale, what I really need is to vary the brightness of a certain region of the image.
(What I'm enclosing is a bit of a mess, but I think it exemplifies well what I need. It's made with photoshop)
  6 Comments
Walter Roberson
Walter Roberson on 9 Apr 2020
Unfortunately my browser still complains that the attached bmp contain errors. Perhaps convert it to png and attach that.

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Accepted Answer

Walter Roberson
Walter Roberson on 9 Apr 2020
Depending on how you are constructing your "complex geometry", sometimes you can construct masks to select pixels. For example you might be able to use poly2mask() . Or sometimes it can be useful to use Computer Vision's insertshape() to paint various shapes into an array, after which you would binarize it (because insertshape() always creates rgb) and use it as the mask.
  5 Comments
Walter Roberson
Walter Roberson on 9 Apr 2020
The question is going to be how you convey to MATLAB which region you are interested in.
Perhaps you might want to use a freehand ROI, such as https://www.mathworks.com/help/images/ref/images.roi.freehand.html
MATLAB does not give any ability to only apply desired functions within a region of interest. But you can createMask() on ROI and use the mask as logical indexes to select data:
mask = createMask(MyROI);
olddata = MyImage(mask);
newdata = imadjust(olddata);
NewImage = MyImage;
NewImage(mask) = newdata;

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